icosahedron
/ˌaɪkoʊsəˈhiːdrən/
noun
- A solid geometric shape with 20 flat triangular faces, 12 vertices, and 30 edges.
- The math teacher showed the class a clear plastic icosahedron to explain its symmetry.
- A classic 20-sided die used in role-playing games is an icosahedron.
- Some viruses have a capsid shaped like an icosahedron for maximum strength.